Diethyl azodiformate

In the photolysis of neat ethyl azidoformate (66) diethyl azodiformate (76) is produced in the early stages of the process, to be later replaced by the triethyl nitrilotriformate (77) which is produced in 58% yield A detailed investigation showed that the nitrilo compound (77) is apparently not formed by the action of a nitrene, and the reaction between an azide and an excited azodiformate was suggested as a possible pathway. Hancock has proposed an alternative mechanism which involves triazacyclopropene (see, however, Huisgen ). 

Diels-Alder dienophile. It is somewhat less reactive in this respect than diethyl azodiformate. 

The elimination of a hydrogen sulfide molecule from thioureas by the use of diethyl azodiformate (78) is also initiated by the same S-N bond formation. 

A soln. of diethyl azodiformate in dry tetrahydrofuran added dropwise at 0-4° under Ng to a stirred soln. of triphenylphosphine, benzophenone oxime, and p-nitrobenzoic acid in the same solvent, warmed to 25°, and stirred 18 hrs. N-benzoyl-N-p-nitrobenzoylaniline. Y 87%. F. e. and reactions s. S. Bittner and... 

Diels-Alder dienophiles a-Acetoxyacrylonitrile. Acetylenedicarboxyhc acid. Acrolein (see 1-o-Nitrophenylbutadiene). Allyl alcohol (see Lithium). 1,4-Benzoquinone (see also 1,4-Naphthoquinone, preparation). /rans-l,2-Dibenzoylethylene. Di-(-butyl azodiformate. Dichloroketene. Dicyanoacetylene. Diethyl acetylenedicarboxylate. 1,4-Dihydronaphthalene-... 

In diethyl maleate the othoxycarbonyl groups are twisted, one up and one down, by 90° from a planar model in which both carbonyl groups are disposed in the same clock-wise sense. In diethyl fumarate and azodiformate opposite twists of ca. 

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